Elongation at Break

Tensile testing is one of the most widely used methods in material science for determining the mechanical properties of materials under uniaxial tension. The process involves applying a controlled pulling force to a specimen until it fractures, allowing engineers and scientists to understand its behaviour under load.

By measuring parameters such as tensile strength, modulus of elasticity, and elongation at break, tensile testing provides essential data for material selection, product design, and quality control. It plays a key role in industries such as aerospace, automotive, medical devices, packaging, and construction, ensuring that materials perform reliably in service.

A typical tensile test involves gripping a standardised sample in a testing machine, applying a steadily increasing tensile force, and recording its response. The resulting stress-strain curve reveals critical mechanical characteristics, which can then be compared against specifications and industry standards.

Elongation at break measures how much a material can stretch before it fractures. Expressed as a percentage of the original gauge length, it is a key indicator of ductility and toughness.

A ductile metal such as aluminium may have a high elongation at break, meaning it can deform significantly before breaking. A brittle material such as glass will have a much lower value.

Key points about elongation at break:

• Indicator of ductility: A high percentage means the material can sustain more deformation, which is important in applications where flexibility is required.
• Material performance insight: When combined with tensile strength, elongation at break provides a complete picture of how a material will perform under real-world conditions.
• Application-specific relevance: For elastomers, textiles, and certain plastics, elongation at break is often a primary quality control measure.

To ensure accuracy and comparability, elongation at break and tensile strength measurements are performed according to recognised industry standards. These standards define specimen geometry, test speeds, environmental conditions, and calculation methods.

Following these standards ensures test results are accurate, repeatable, and comparable between laboratories and production facilities.

While the specifics vary depending on material type and applicable standards, the general procedure includes:

Specimen preparation

• Prepare samples according to the standard’s geometry requirements.
• Measure the original gauge length and cross-sectional area accurately.

Equipment setup

• Mount the specimen in the grips of a universal testing machine (UTM) or specialised tensile tester.
• Ensure correct alignment to avoid bending stresses that may distort results.

Test execution

• Apply a tensile force at the specified constant crosshead speed.
• Continuously record load and extension until the specimen fractures.

Data analysis

• Generate a stress-strain curve from recorded data.
• Calculate elongation at break by comparing the final gauge length to the original.

Reporting

• Report tensile strength, modulus, and elongation at break, along with environmental test conditions.

Different materials require adjustments. Elastomers may need lower strain rates, metals can withstand higher loads, and textiles often need specialised clamping to avoid slippage.

Tensile testing and elongation at break analysis are vital across many industries:

• Plastics and rubbers: Quality control for packaging films, seals, gaskets, and elastomeric components.
• Metals: Verification of ductility and strength for automotive body panels, aerospace-grade aluminium fuselage sections, and structural steel.
• Textiles: Assessing durability and elasticity in fabrics for clothing, upholstery, and industrial use.
• Construction materials: Evaluating steel reinforcement bars, cables, and composite panels.
• Medical devices: Testing catheters, sutures, and implant materials for flexibility and resilience.

In each application, elongation at break helps determine whether a material can meet its performance demands in service.

Mecmesin offers a wide range of tensile testing systems designed for accurate, repeatable measurement of elongation at break across materials and industries.

Standards-aligned testing solutions

Our systems, including the OmniTest and MultiTest-dV ranges, are designed to comply with ASTM, ISO, and BS EN standards. They offer fine control over test speeds, grip configurations, and environmental conditions to ensure accuracy and reliability.

Versatile equipment for every application

From bench-top single-column testers for lighter materials to high-capacity twin-column systems for metals and composites, Mecmesin provides scalable solutions. A wide range of grips and fixtures allows testing of plastics, rubbers, textiles, and metals.

Advanced software integration

With Mecmesin’s VectorPro software, users can:

• Capture detailed stress-strain data in real time.
• Automatically calculate elongation at break.
• Store and manage test data securely for quality records.

Tensile testing and elongation at break measurement are essential for material performance evaluation, product development, and quality assurance. For advice on selecting the most suitable tensile testing solution for your application, speak to a Mecmesin specialist. Our experts can help you achieve reliable, standards-compliant results tailored to your industry needs.